Coach,
If you have some time, here is a pretty detailed excerpt from UpToDate.com, which is one of the "go-to's" of many Internal Medicine Doctors and general practitioners (PCP).
TREATMENT — Acute viral gastroenteritis is usually self-limited and is treated with supportive measures (fluid repletion and unrestricted nutrition). No specific antiviral agents are available.
For adults presenting with acute viral gastroenteritis without signs of volume depletion, adequate volume can be maintained with sport drinks and broths. For adults presenting with mild to moderate hypovolemia, oral rehydration solutions may be superior to sports drinks in maintaining electrolyte balance along with hydration. Patients with severe dehydration require intravenous fluids (algorithm 2). (See "Approach to the adult with acute diarrhea in developed countries", section on 'Oral rehydration solutions'.)
Antiemetics and antimotility agents are used sometimes for excessive vomiting or excessive fluid loss from diarrhea, respectively. In known viral gastroenteritis epidemics, antibiotics are not indicated. Empiric antibiotics may have a limited role in the management of acute gastroenteritis, when it is unclear if the etiology is viral or bacterial. The role of antibiotics in bacterial gastroenteritis is discussed separately. (See "Approach to the adult with acute diarrhea in developed countries", section on 'Empiric antibiotic therapy'.)
Supportive measures — In the 1960s, the discovery that the intestines of patients with cholera could still absorb water and electrolytes, despite secreting large amounts of fluid, laid the foundation for fluid maintenance and repletion as a mainstay of the management of acute gastroenteritis [15]. To this day, treatment for acute viral gastroenteritis consists primarily of supportive measures.
Fluid maintenance and repletion — For adults presenting with acute viral gastroenteritis without signs of volume depletion, adequate volume can be maintained with sports drinks and broths. Soft drinks and fruit juices that are high in sugar content should be avoided. For adults presenting with mild to moderate volume depletion (table 2), oral rehydration solutions may be superior to sports drinks in maintaining electrolyte balance along with hydration. World Health Organization oral rehydration solution (WHO-ORS) is available from Jianas Brothers, Rehydralyte from Ross Laboratories, or Cera-lyte. For patients with severe hypovolemia, or an inability to tolerate oral rehydration, repletion with intravenous normal saline or Ringer’s lactate is required (algorithm 2).
Oral rehydration has been associated with a higher risk of paralytic ileus while intravenous hydration carries the risk of phlebitis [16,17]. Oral rehydration should not be used if the patient has impaired mental status or abdominal ileus. In resource poor environments in developing countries, where access to medical care and intravenous fluids may be limited, oral rehydration may be particularly useful.
The principles of oral hydration in adults are based primarily on studies showing a benefit in children [18]. In children, the use of the standard WHO-ORS decreases the mortality due to acute diarrheal illnesses. There is very limited data in adults. A small randomized trial of 60 adults in India with dehydration from viral gastroenteritis showed that adults randomized to Gatorade, a modified ORS, and Pedialyte had similar improvements in diarrheal symptoms and body weight [19]. However, the ORS and Pedialyte were effective in correcting hypokalemia, but the Gatorade was not. (See "Approach to the adult with acute diarrhea in developed countries", section on 'Oral rehydration solutions' and "Approach to the adult with acute diarrhea in developing countries", section on 'Rehydration'.)
Intravenous replacement fluid therapy is discussed in detail separately. (See "Maintenance and replacement fluid therapy in adults", section on 'Replacement fluid therapy'.)
Diet — In adults with acute viral gastroenteritis, we do not recommend adherence to any restricted diet. Patients should be encouraged to eat as tolerated. Smaller meals may be less likely to induce vomiting than larger ones. Bland, low residue foods may also be better tolerated than others. For healthy adults with acute viral gastroenteritis without signs of dehydration, sport drinks, diluted fruit juices, and other flavored soft drinks augmented with saltine crackers and broths or soups can meet the fluid and salt needs in almost all cases. Broiled starches/cereals (potatoes, noodles, rice, wheat, and oat) with some salt are excellent foods to consider. In addition, crackers, bananas, yogurt, soups, and boiled vegetables can also be consumed.
While the BRAT diet (bananas, rice, applesauce, and toast) is often recommended, the evidence to support it is weak [20]. Similarly, while many authorities advise patients to exclude milk and dairy products from their diet during the episode of diarrhea and for several weeks after symptoms resolve, the evidence to support this is weak [21]. A 2008 systematic review of 71 studies concluded that there is limited evidence in adults to support dietary restrictions and that restricted and unrestricted diets seem to be equally effective at reducing the duration of watery and non-watery diarrhea [22].
Probiotics — The value of oral probiotics in acute viral gastroenteritis is not well established, and further research is needed to determine the optimal type, dose, and regimen of probiotics before they are recommended for routine use.
Probiotics may modulate the immune response through interaction with the gut-associated immune system or through direct effect on other microorganisms [23]. Multiple systematic reviews have demonstrated a modest reduction in the duration of infectious diarrhea with the use of probiotics, although there was heterogeneity among studies [24-31]. (See "Probiotics for gastrointestinal diseases", section on 'Infectious diarrhea'.)
Zinc — The effect of zinc supplementation on duration of diarrheal illnesses in adults has not been studied, and its use is not the standard of care. The WHO/UNICEF recommends zinc for children with acute diarrhea [32,33], since diarrhea may cause zinc deficiency resulting in longer duration and severity of symptoms [34]. In developing countries where mild to moderate zinc deficiency is highly prevalent, this may affect recovery from acute gastroenteritis [32].
Pharmacotherapy — In general, viral gastroenteritis is an acute and self-limited disease that does not require pharmacologic therapy. The goals of adding pharmacotherapy, when indicated, to the management of acute viral gastroenteritis are to decrease fluid losses (using antimotility agents) and to allow adequate oral rehydration (using antiemetics). It is important to remember that adequate fluid repletion is the mainstay of treatment of acute viral gastroenteritis, and that any pharmacologic agents are to be used as adjuncts, and not to replace adequate fluid repletion.
Antimotility agents — In adults younger than 65 years of age with acute viral gastroenteritis and with moderate to severe diarrhea or signs or symptoms of volume depletion (table 2), we suggest a one- to two-day course of loperamide (4 mg orally, followed by 2 mg after each episode of diarrhea, up to 8 mg/day) as an adjunctive treatment to supportive measures. Patients may take the over-the-counter formulation, but should be advised not to exceed two days. For adults ≥65 years of age, loperamide is not recommended for self-medication, and patients should be closely monitored if taking it under the guidance of a physician.
Loperamide is an over-the-counter product in the United States. Loperamide inhibits intestinal peristalsis and has antisecretory properties, but does not penetrate the central nervous system and has no substantial potential for addiction [9,35]. According to a systematic review of seven randomized trials in adults with acute diarrhea from a variety of causes, treatment with loperamide reduced the duration of diarrhea compared with placebo [22]. As an example, in one included trial, 230 adults were randomized to receive loperamide oxide (1 or 2 mg) or placebo after each loose stool (maximum of eight tablets in the active groups) [36]. The median time to complete relief was reduced by 12 to 15 hours in the loperamide groups compared to placebo.
Constipation is a common side effect of loperamide, and the risk is increased for older adults [37]. The risk for constipation can be reduced by the use of loperamide only as needed for each loose stool, rather than scheduled daily dosing, and by limiting its use to two days. Paralytic ileus is an uncommon, but serious, adverse event. Loperamide should be used with caution in patients with hepatic impairment and with monitoring for signs of mental status changes. Patients should stop taking loperamide if they develop constipation, abdominal distention, or worsening abdominal pain. In addition, antimotility agents should be avoided in patients with bloody diarrhea, as the presence of bloody diarrhea indicates the presence of a non-viral cause of gastroenteritis that should be evaluated further [5]. The use of antimotility agents in some types of non-viral diarrheal illness (eg, Clostridium difficile colitis) could be potentially harmful. (See 'Differential diagnosis' above and "Clostridium difficile in adults: Treatment", section on 'General management principles'.)
Antiemetics — Although studies in adult populations are lacking, for patients who cannot tolerate oral rehydration due to excessive vomiting, we suggest treating with an antiemetic (eg, prochlorperazine or ondansetron) as needed for one to two days to facilitate oral fluid repletion.
A systematic review of 10 randomized trials compared various antiemetics (dexamethasone, dimenhydrinate, granisetron, metoclopramide, and ondansetron) prescribed for children who presented with vomiting and a confirmed clinical diagnosis of acute gastroenteritis [38]. Ondansetron increased the proportion of children with cessation of vomiting, reduced the immediate hospital admission rate and the need for intravenous rehydration therapy.
Antibiotics — In adults who clearly have acute viral gastroenteritis (eg, outbreak with known etiology), we do not recommend the empiric use of antibiotics. In general, empiric therapy for community-acquired acute diarrhea (of unclear etiology) may be beneficial but does not appear to dramatically alter the course of illness in unselected populations. If patients initially treated with supportive measures do not improve after seven days or symptoms worsen, then they should be reevaluated and possibly treated for other causes of gastroenteritis. (See 'Differential diagnosis' above and "Approach to the adult with acute diarrhea in developed countries", section on 'Empiric antibiotic therapy'.)
When to hospitalize — Most individuals with acute viral gastroenteritis can be managed in the outpatient setting. Potential indications for hospitalization include the presence of alarm symptoms or signs (table 1), or individuals at risk for complications (eg, dehydration), including [39]:
Volume depletion/dehydration
Intractable vomiting
Abnormal electrolytes or renal function
Excessive bloody stool or rectal bleeding
Severe abdominal pain
Prolonged symptoms (more than one week)
Age 65 or older with signs of hypovolemia
Comorbidities (eg, diabetes mellitus, immunocompromised)
Pregnancy
PROGNOSIS/COMPLICATIONS — Acute viral gastroenteritis is usually transient and self-limited with an excellent prognosis. In developed countries, hospital admission for acute gastroenteritis is uncommon but necessary when severe dehydration is present. Older frail adults are also more susceptible to dehydration and subsequent complications (eg, syncope, hypotension) [9]. Persons with medical comorbidities, such as immunodeficiency, inflammatory bowel disease, valvular heart disease, diabetes mellitus, renal impairment, rheumatoid arthritis, systemic lupus erythematosus, as well as patients taking immunosuppressants, systemic corticosteroids, or diuretics, are more vulnerable and at risk for complications and poor outcomes [40]. These patients require closer follow-up and a lower threshold for hospitalization or further evaluation if the gastroenteritis is not resolving.
Acute gastroenteritis usually has no long-term sequelae. In developed countries, 75 percent of adults fully recover from acute gastroenteritis, but an estimated 25 percent of them have long-lasting changes in their bowel habits and a smaller number of these individuals will develop post-infectious irritable bowel syndrome [41]. (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults".)
PREVENTION — Prevention occurs at both the individual and community level. The best preventive measure that individuals can take is adequate hand hygiene and avoidance of close contact, if possible, with people with symptoms of gastroenteritis. Individuals with acute gastroenteritis should be counseled about diligent hand hygiene to help prevent spread of infection to their family, colleagues, and contacts.
Appropriate community infection control measures partially depend on the epidemiologic setting in which viral gastroenteritis is taking place. For disease outbreaks occurring in healthcare and long-term care facilities (typically caused by norovirus [42-44]), standard enteric precaution measures involve careful handwashing and use of barriers, such as wearing gloves. A meta-analysis, not limited to viral gastroenteritis, suggested that handwashing with soap reduces diarrheal risk by 47 percent [45]. Cohorting of patients may become necessary in outbreaks that are slow to control. Similar measures should be employed in acute care hospitals for adults [43]. (See "Epidemiology, clinical manifestations and diagnosis of norovirus and related viruses", section on 'Infection control'.)
In outbreaks from contamination of an identified water or food source, public health measures should be directed at identified sources [42,46,47]. Most foodborne cases of gastroenteritis in the United States are due to norovirus [47]; contamination of food occurs either at the environmental source (eg, oysters or raspberries) or by food handlers [48]. Recurring norovirus outbreaks on cruise ships have presented difficult problems in infection control requiring isolation of ill crew members (and passengers, if possible) and disinfection of ships with chlorine solutions, phenol-based compounds, or accelerated hydrogen peroxide products [49]. Norovirus is a very stable agent that easily persists in the environment and is notoriously difficult to eradicate; it persists after treatment with chlorine solutions that are well beyond concentrations present in public water systems [50]. Norovirus is the most infectious of viral pathogens, with a median infectious dose of only 18 viruses, which further compounds problems for eradication [51].
Good luck Coach,
"1"
